perf/arm-spe: Assign parents for event_source device

Currently the PMU device appears directly under /sys/devices/
Only root busses should appear there, so instead assign the pmu->dev
parent to be the platform device.

Link: https://lore.kernel.org/linux-cxl/ZCLI9A40PJsyqAmq@kroah.com/
Acked-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Link: https://lore.kernel.org/r/20240412161057.14099-24-Jonathan.Cameron@huawei.com
Signed-off-by: Will Deacon <will@kernel.org>

Author: jic23

drivers/perf/arm_spe_pmu.c

@@ -932,6 +932,7 @@ static int arm_spe_pmu_perf_init(struct arm_spe_pmu *spe_pmu)
 
 	spe_pmu->pmu = (struct pmu) {
 		.module = THIS_MODULE,
+		.parent		= &spe_pmu->pdev->dev,
 		.capabilities	= PERF_PMU_CAP_EXCLUSIVE | PERF_PMU_CAP_ITRACE,
 		.attr_groups	= arm_spe_pmu_attr_groups,
 		/*